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United States Patent |
6,235,821
|
Saito
|
May 22, 2001
|
Cleansing thermoplastic resin composition
Abstract
The invention provides thermoplastic resin compositions for purging which
comprise a thermoplastic resin and a methyl methacrylate/styrene copolymer
incorporated therein. According to the invention, thermoplastic resin
compositions for purging molding machines, which have an excellent
cleaning ability, can be obtained.
Inventors:
|
Saito; Takanori (Chiba, JP)
|
Assignee:
|
Chisso Corporation (Osaka, JP)
|
Appl. No.:
|
402250 |
Filed:
|
December 8, 1999 |
PCT Filed:
|
April 1, 1998
|
PCT NO:
|
PCT/JP98/01509
|
371 Date:
|
December 8, 1999
|
102(e) Date:
|
December 8, 1999
|
PCT PUB.NO.:
|
WO98/44048 |
PCT PUB. Date:
|
October 8, 1998 |
Foreign Application Priority Data
Current U.S. Class: |
524/161; 524/515; 524/523; 525/330.3 |
Intern'l Class: |
C08K 005/42; C08L 033/12 |
Field of Search: |
524/161,523,525,528,513,515
525/190,195,330.3
|
References Cited
U.S. Patent Documents
3909478 | Sep., 1975 | Riess et al.
| |
4377664 | Mar., 1983 | Bourland.
| |
4692295 | Sep., 1987 | Vinatier.
| |
4713310 | Dec., 1987 | Horie.
| |
4940747 | Jul., 1990 | Eichenauer et al. | 524/526.
|
5447989 | Sep., 1995 | Mylonakis et al. | 525/67.
|
5696187 | Dec., 1997 | Kokuzawa et al. | 524/161.
|
5717021 | Feb., 1998 | Huang et al. | 524/525.
|
Foreign Patent Documents |
0234529 | Sep., 1987 | EP.
| |
0 432 585 A2 | Jun., 1991 | EP.
| |
0010937 | Apr., 1973 | JP.
| |
5-98072 | Apr., 1993 | JP.
| |
5-98298 | Apr., 1993 | JP.
| |
Primary Examiner: Yoon; Tae H.
Attorney, Agent or Firm: Leydig, Voit & Mayer, Ltd
Claims
What is claimed is:
1. A purging thermoplastic resin composition which comprises a
thermoplastic resin comprising at least one compound selected from the
group consisting of polypropylene, high-density polyethylene, low-density
polyethylene, linear low-density polyethylene, poly(ethylene
terephthalate), poly(butylene terephthalate), polystyrene,
acrylonitrile/butadiene/styrene copolymers, acrylonitrile/styrene
copolymers and poly(methyl methacrylate);
a methyl methacrylate/styrene copolymer having a number-average molecular
weight of from 10,000 to 150,000 in an amount of from 0.5 to 10% by weight
based on the weight of the composition; and
a metal salt of an alkylbenzenesulfonic acid in amount of from 1 to 30% by
weight based on the weight of the composition.
2. The purging thermoplastic resin composition according to claim 1,
wherein the alkyl group in the metal salt of an alkylbenzenesulfonic acid
has from 6 to 20 carbon atoms and the metal salt is a salt of sodium,
calcium, magnesium or potassium.
Description
TECHNICAL FIELD
The present invention relates to purging thermoplastic resin compositions
for use in the purging of molding machines for thermoplastic resins. More
particularly, this invention relates to a thermoplastic resin composition
for purging which comprises a thermoplastic resin and a methyl
methacrylate/styrene copolymer and a thermoplastic resin composition for
purging which comprises a thermoplastic resin, a methyl
methacrylate/styrene copolymer, and a metal salt of an
alkylbenzenesulfonic acid.
BACKGROUND ART
In the molding of plastics, change of a resin being used has conventionally
necessitated various means for eliminating the influences of the preceding
resin. Especially in the molding of colored resins, when the resin to be
molded is changed from one of a dark color, e.g., blue or black, to one of
a light color, e.g., white, a complicated cleaning operation has been
necessary which comprises, for example, disassembling and cleaning the
molding machine or purging the molding machine with a general or reclaimed
resin or the like and is accompanied by a prolonged suspension of
production. As a means for eliminating these problems, various
thermoplastic resin compositions for purging molding machines have been
developed.
For example, Unexamined Published Japanese Patent Application No. 62-195045
proposes a composition obtained by incorporating a sodium
alkylbenzenesulfonate and a water-repellent compound (a metal salt of a
higher fatty acid, wax, liquid paraffin, synthetic wax, etc.) into a
thermoplastic resin in respective amounts of from 2 to 30% by weight and
from 0.5 to 10% by weight based on the composition; Unexamined Published
Japanese Patent Application No. 05-060768 proposes a composition obtained
by incorporating the calcium salt of a boric ester of a higher fatty acid
monoglyceride and an inorganic filler into a thermoplastic resin; and
Unexamined Published Japanese Patent Application No. 03-283805 proposes a
purging composition obtained by incorporating a neutral salt of an
alkylbenzenesulfonic acid and basic magnesium stearate into a
thermoplastic resin in respective amounts of from 2 to 40% by weight and
from 1 to 10% by weight based on the composition.
However, the conventional purging compositions described above are still
insufficient in cleaning ability, and there is a desire for a
thermoplastic resin composition for purging which has a high cleaning
ability.
As apparent from the above description, an object of the present invention
is to provide a thermoplastic resin composition for purging a molding
machine, which has an excellent cleaning ability.
DISCLOSURE OF THE INVENTION
The present inventor made extensive studies in order to develop a purging
resin composition having an excellent cleaning ability. As a result, it
has been found that a composition comprising a thermoplastic resin and a
methyl methacrylate/styrene copolymer contained therein and a composition
comprising the above composition and further a metal salt of an
alkylbenzenesulfonic acid contained therein are purging thermoplastic
resin compositions having an excellent cleaning ability. The present
invention has been completed based on this finding.
The present invention has the following constitutions.
(1) A thermoplastic resin composition for purging, which comprises a
thermoplastic resin and a methyl methacrylate/styrene copolymer contained
in the thermoplastic resin.
(2) The thermoplastic resin composition for purging as described in the
above (1), wherein the methyl methacrylate/styrene copolymer is contained
in an amount of from 1 to 30% by weight based on the composition.
(3) The thermoplastic resin composition for purging as described in the
above (1), wherein the thermoplastic resin further contains the methyl
methacrylate/styrene copolymer and a metal salt of an alkylbenzenesulfonic
acid.
(4) The thermoplastic resin composition for purging as described in the
above (3), wherein the methyl methacrylate/styrene copolymer and the metal
salt of an alkylbenzenesulfonic acid are contained in amounts of from 0.5
to 10% by weight and from 1 to 30% by weight, respectively, based on the
composition.
(5) The thermoplastic resin composition for purging as described in any one
of the above (1) to (4), wherein the methyl methacrylate/styrene copolymer
has a number-average molecular weight of from 10,000 to 150,000.
(6) The thermoplastic resin composition for purging as described in the
above (3) or (4), wherein the alkyl group in the metal salt of an
alkylbenzenesulfonic acid has from 6 to 20 carbon atoms and the metal salt
is a salt of sodium, calcium, magnesium or potassium.
(7) The thermoplastic resin composition for purging as described in any one
of the above (1) to (4), wherein the thermoplastic resin comprises at
least one compound selected from polypropylene, high-density polyethylene,
low-density polyethylene, linear low-density polyethylene, poly(ethylene
terephthalate), poly(butylene terephthalate), polystyrene,
acrylonitrile/butadiene/styrene copolymers, acrylonitrile/styrene
copolymers, and poly(methyl methacrylate).
BEST MODES FOR CARRYING OUT THE INVENTION
The thermoplastic resin for use in the present invention means a resin
which is capable of repeatedly undergoing a cycle in which the resin, upon
heating, softens and fluidizes with increasing temperature and, upon
cooling, comes into a relatively rigid state having a strength. The
thermoplastic resin is not particularly limited as long as it has the
above property. However, from the standpoint of obtaining a purging
thermoplastic resin composition which has a satisfactory cleaning ability,
in particular, which is less apt to remain in the molding machine or
extruder and is capable of shortening the time period required for
purging, it is preferred to use one or more thermoplastic resins selected
from polypropylene, high-density polyethylene, low-density polyethylene,
linear low-density polyethylene, poly(ethylene terephthalate),
poly(butylene terephthalate), polystyrene, acrylonitrile/butadiene/styrene
copolymers, acrylonitrile/styrene copolymers, and poly(methyl
methacrylate). These thermoplastic resins may be used alone or as a
mixture of two or more thereof. These resins are not limited to fresh
ones, and may be reclaimed ones for recycling which have been obtained by
recovering used resins and pulverizing the same.
The methyl methacrylate/styrene copolymer for use in the present invention
is not particularly limited as long as it is a polymer obtained by
copolymerizing methyl methacrylate and styrene. However, from the
standpoint of attaining an excellent cleaning ability, the copolymer has a
number-average molecular weight of preferably from 10,000 to 150,000, more
preferably from 30,000 to 100,000, especially preferably from 50,000 to
80,000.
From the standpoints of cleaning ability and the replaceability of the
composition itself with a succeeding resin, methacrylic acid and styrene
are copolymerized in such a ratio that the proportion of methyl
methacrylate is preferably from 5 to 50% by weight, more preferably from
10 to 40% by weight, especially preferably from 15 to 30% by weight.
The methyl methacrylate/styrene copolymer for use in the present invention
can be obtained by a known process, e.g., the suspension polymerization
method or emulsion polymerization method. The suspension polymerization
method, for example, comprises introducing pure water, styrene monomer,
methyl methacrylate monomer, poly(vinyl alcohol) as a dispersant, and
lauroyl peroxide as a polymerization initiator into a vessel equipped with
a stirrer and heating the resultant mixture to 70 to 80.degree. C. with
stirring to copolymerize the monomers. The copolymer slurry obtained is
dehydrated with a centrifugal separator and dried in an air stream,
whereby the target copolymer can be obtained as a powder. Commercially
available products can also be used. Examples thereof include New Frontier
MS-750P (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.).
The metal salt of an alkylbenzenesulfonic acid for use in the present
invention may be an industrially produced one in which the alkyl group has
preferably 6 to 20 carbon atoms, more preferably 8 to 17 carbon atoms,
especially preferably 10 to 14 carbon atoms, and the metal salt is
preferably a salt of sodium, calcium, magnesium or potassium, especially
preferably a salt of sodium or magnesium.
In the thermoplastic resin composition for purging of the present invention
which comprises a thermoplastic resin and a methyl methacrylate/styrene
copolymer, the content of the methyl methacrylate/styrene copolymer is not
particularly limited. However, in order to enable the composition to have
an excellent cleaning ability, the amount of the methyl
methacrylate/styrene copolymer incorporated in the thermoplastic resin is
preferably from 1 to 30% by weight, more preferably from 3 to 20% by
weight, especially preferably from 5 to 15% by weight, based on the
composition.
In the thermoplastic resin composition for purging of the present invention
which comprises a thermoplastic resin, a methyl methacrylate/styrene
copolymer, and a metal salt of an alkylbenzenesulfonic acid, the content
of the methyl methacrylate/styrene copolymer is not particularly limited.
However, in order to enable the composition to have an excellent cleaning
ability, the content thereof is preferably from 0.5 to 10% by weight, more
preferably from 1 to 6% by weight, especially preferably from 1.5 to 4% by
weight, based on the composition. The content of the metal salt of an
alkylbenzenesulfonic acid in the composition is also not particularly
limited. However, in order to enable the composition to have an excellent
cleaning ability, the content thereof is preferably from 1 to 30% by
weight, more preferably from 3 to 20% by weight, especially preferably
from 5 to 10% by weight, based on the composition.
An inorganic filler such as, e.g., calcium carbonate, basic magnesium
carbonate, basic magnesium stearate, talc, silica, alumina, or glass
fibers can be added to the compositions of the present invention if
desired and necessary. It is also possible to add a metal soap such as,
e.g., calcium stearate, magnesium stearate, or zinc stearate or a wax such
as, e.g., carnauba wax or polyethylene wax.
The compositions of the present invention can be obtained by mixing a
thermoplastic resin and a methyl methacrylate/styrene copolymer in
respective desired amounts or mixing these ingredients and a metal salt of
an alkylbenzenesulfonic acid in respective desired amounts by means of a
stirring mixer. The compositions can be obtained also by melt-kneading the
resultant mixture at a melt-kneading temperature of from 180 to
300.degree. C. and extruding the melt into pellets. The stirring mixer may
be an ordinarily used one such as, e.g., a Henschel mixer (trade name),
supermixer, tumbling mixer, or ribbon blender. An extruder such as, e.g.,
a single-screw extruder, twin-screw extruder, or co-kneader may be used.
EXAMPLES
The present invention will be explained below in detail by reference to
Examples and Comparative Examples, but the invention should not be
construed as being limited thereto. In the Examples and Comparative
Examples, cleaning ability was evaluated through the following purging
test (1) or (2).
Purging Test (1):
A flame-retardant polypropylene composition (property: black) composed of:
84 wt % of polypropylene having a melt flow rate (JIS K7210: 230.degree.
C., 21.18 N load; hereinafter abbreviated as "MFR (1)") of 6.0 g/10 min
and a crystal melting point of 165.degree. C.; 10 wt % of
bist{[3,5-dibromo-4-(2',3'-dibromopropoxy)]phenyl}sulfone; 5 wt % of
antimony trioxide; and 1 wt % of carbon black was extruded for about 60
minutes with a single-screw extruder (cylinder diameter: 35 mm, L/D: 30)
at a rotational screw speed of 150 rpm, a discharge rate of 5 kg/h, and an
extrusion temperature of 200.degree. C. A thermoplastic resin composition
for purging (property: milk-white or light yellow) was fed in place of the
flame-retardant polypropylene composition to the extruder in which the
flame-retardant polypropylene composition still remained. The purging
thermoplastic resin composition was extruded and the amount thereof
required for the black color of the flame-retardant polypropylene
composition to disappear was measured. Subsequently, polypropylene having
an MFR (1) of 6.0 g/10 min and a crystal melting point of 165.degree. C.
was fed as a succeeding resin for purging in place of the purging
thermoplastic resin composition. The purging polypropylene as a succeeding
resin was extruded and the amount thereof required for the color of the
purging thermoplastic resin composition to disappear was measured.
Furthermore, the time period required from initiation of the extrusion of
the purging thermoplastic resin composition to disappearance of the color
of the purging thermoplastic resin composition was measured.
The above amounts and period were used as measures of cleaning ability.
Purging Test (2):
A flame-retardant ABS resin composition (property: black) composed of: 84
wt % of ABS resin having a specific gravity of 1.05 and a melt flow rate
(JIS K7210: 220.degree. C., 98.07 N load; hereinafter abbreviated as "MFR
(2)") of 9 g/10 min (trade name, ABS 45; manufactured by Japan Synthetic
Rubber Co., Ltd.); 10 wt % of
2,2-bis{[3,5-dibromo-4-(2',3'-dibromopropoxy)]phenyl}propane; 5 wt % of
antimony trioxide; and 1 wt % of carbon black was extruded for about 60
minutes with a single-screw extruder (cylinder diameter: 35 mm, L/D: 30)
at a rotational screw speed of 150 rpm, a discharge rate of 5 kg/h, and an
extrusion temperature of 220.degree. C. Subsequently, a thermoplastic
resin composition for purging (property: milk-white or light yellow) was
fed in place of the flame-retardant ABS resin composition to the extruder
(in which the flame-retardant ABS resin composition still remained). The
purging thermoplastic resin composition was extruded and the amount
thereof required for the black color of the flame-retardant ABS resin
composition to disappear was measured. Subsequently, an ABS resin
(property: light yellow) having a specific gravity of 1.05 and an MFR (2)
of 9 g/10 min (trade name, ABS 45; manufactured by Japan Synthetic Rubber
Co., Ltd.) was fed as a succeeding resin for purging in place of the
purging thermoplastic resin composition. The purging ABS resin composition
as a succeeding resin was extruded and the amount thereof required for the
color of the purging thermoplastic resin composition to disappear was
measured. Furthermore, the time period required from initiation of the
extrusion of the purging thermoplastic resin composition to disappearance
of the color of the purging thermoplastic resin composition was measured.
The above amounts and period were used as measures of cleaning ability.
Example 1
Into a Henschel mixer having a capacity of 20 liters were introduced 4.80
kg (96.0 wt %) of polypropylene having an MFR (1) of 0.5 g/10 min and a
crystal melting point of 165.degree. C. and 0.10 kg (4.0 wt %) of a methyl
methacrylate/styrene copolymer having a number-average molecular weight of
67,000 and a methyl methacrylate/styrene copolymerization ratio of 25/75
in terms of wt % (trade name, New Frontier MS-750P; manufactured by
Dai-ichi Kogyo Seiyaku Co., Ltd.; hereinafter abbreviated as MMSC). The
contents were stirred and mixed for 3 minutes at a rotational speed of 500
rpm. The mixture obtained was fed to a twin-screw extruder (cylinder
diameter, 30 mm; L/D, 30) and melt-kneaded and extruded at a cylinder
temperature of 190 to 200.degree. C. and a die temperature of 200.degree.
C. The extrudate was cooled in a water bath and cut with a pelletizer to
obtain a thermoplastic resin composition for purging (property:
milk-white). This thermoplastic resin composition for purging was used to
conduct the purging test (1) described above. As a result, the required
amount of the purging thermoplastic resin composition was 1.1 kg and that
of the polypropylene as a succeeding resin for purging was 1.3 kg. The
time period required was 29 minutes.
Example 2
A thermoplastic resin composition for purging (property: milk-white) was
obtained in the same manner as in Example 1, except that 4.975 kg (99.5 wt
%) of polypropylene having an MFR (1) of 0.5 g/10 min and a crystal
melting point of 165.degree. C. and 0.025 kg (0.5 wt %) of the MMSC were
used. This thermoplastic resin composition for purging was used to conduct
the purging test (1). As a result, the required amount of the purging
thermoplastic resin composition was 2.3 kg and that of the polypropylene
as a succeeding resin for purging was 1.7 kg. The time period required was
49 minutes.
Example 3
A thermoplastic resin composition for purging (property: milk-white) was
obtained in the same manner as in Example 1, except that 4.45 kg (89.0 wt
%) of high-density polyethylene having a melt flow rate (JIS K7210:
190.degree. C., 21.18 N load; hereinafter abbreviated as MFR (3)) of 0.5
g/10 min and a density of 0.95 g/cm.sup.3 and 0.55 kg (11 wt %) of the
MMSC were used. This thermoplastic resin composition for purging was used
to conduct the purging test (1). As a result, the required amount of the
purging thermoplastic resin composition was 0.6 kg and that of the
polypropylene as a succeeding resin for purging was 0.9 kg. The time
period required was 18 minutes.
Example 4
A thermoplastic resin composition for purging (property: light yellow) was
obtained in the same manner as in Example 1, except that 4.05 kg (81.0 wt
%) of an ABS resin having a specific gravity of 1.03 and an MFR (2) of 0.4
g/10 min (PA-709, manufactured by Chimei Corporation) and 0.95 kg (19.0 wt
%) of the MMSC were used. This thermoplastic resin composition for purging
was used to conduct the purging test (2). As a result, the required amount
of the purging thermoplastic resin composition was 0.6 kg and that of the
ABS resin as a succeeding resin for purging was 1.5 kg. The time period
required was 26 minutes.
Example 5
A thermoplastic resin composition for purging (property: light yellow) was
obtained in the same manner as in Example 1, except that 3.35 kg (67 wt %)
of an ABS resin having a specific gravity of 1.03 and an MFR (2) of 0.4
g/10 min (PA-709, manufactured by Chimei Corporation) and 1.65 kg (33 wt
%) of the MMSC were used. This thermoplastic resin composition for purging
was used to conduct the purging test (2). As a result, the required amount
of the purging thermoplastic resin composition was 1.6 kg and that of the
ABS resin as a succeeding resin for purging was 2.3 kg. The time period
required was 47 minutes.
Example 6
A thermoplastic resin composition for purging (property: milk-white) was
obtained in the same manner as in Example 1, except that 3.65 kg (73.0 wt
%) of polystyrene having a melt flow rate (JIS K7210: 200.degree. C.,
49.03 N load; hereinafter abbreviated as MFR (4)) of 0.5 g/10 min and a
density (specific gravity) of 1.05 and 1.35 kg (27.0 wt %) of the MMSC
were used. This thermoplastic resin composition for purging was used to
conduct the purging test (2). As a result, the required amount of the
purging thermoplastic resin composition was 0.7 kg and that of the ABS
resin as a succeeding resin for purging was 1.9 kg. The time period
required was 32 minutes.
Example 7
A thermoplastic resin composition for purging (property: milk-white) was
obtained in the same manner as in Example 1, except that 4.00 kg (80.0 wt
%) of polypropylene having an MFR (1) of 0.5 g/10 min and a crystal
melting point of 165.degree. C., 0.50 kg (10.0 wt %) of the MMSC, and 0.50
kg (10.0 wt %) of sodium dodecylbenzenesulfonate were used. This
thermoplastic resin composition for purging was used to conduct the
purging test (1). As a result, the required amount of the purging
thermoplastic resin composition was 1.0 kg and that of the polypropylene
as a succeeding resin for purging was 1.4 kg. The time period required was
29 minutes.
Example 8
A thermoplastic resin composition for purging (property: milk-white) was
obtained in the same manner as in Example 1, except that 4.965 kg (99.3 wt
%) of polypropylene having an MFR (1) of 0.5 g/10 min and a crystal
melting point of 165.degree. C., 0.010 kg (0.2 wt %) of the MMSC, and
0.025 kg (0.5 wt %) of sodium dodecylbenzenesulfonate were used. This
thermoplastic resin composition for purging was used to conduct the
purging test (1). As a result, the required amount of the purging
thermoplastic resin composition was 2.4 kg and that of the polypropylene
as a succeeding resin for purging was 1.3 kg. The time period required was
45 minutes.
Example 9
A thermoplastic resin composition for purging (property: milk-white) was
obtained in the same manner as in Example 1, except that 4.59 kg (91.8 wt
%) of polypropylene having an MFR (1) of 0.5 g/10 min and a crystal
melting point of 165.degree. C., 0.01 kg (0.2 wt %) of the MMSC, and 0.40
kg (8.0 wt %) of sodium dodecylbenzenesulfonate were used. This
thermoplastic resin composition for purging was used to conduct the
purging test (1). As a result, the required amount of the purging
thermoplastic resin composition was 1.7 kg and that of the polypropylene
as a succeeding resin for purging was 1.5 kg. The time period required was
39 minutes.
Example 10
A thermoplastic resin composition for purging (property: milk-white) was
obtained in the same manner as in Example 1, except that 4.00 kg (80.0 wt
%) of high-density polyethylene having an MFR (3) of 0.5 g/10 min and a
density of 0.95 g/cm.sup.3, 0.25 kg (5.0 wt %) of the MMSC, and 0.75 kg
(15.0 wt %) of sodium dodecylbenzenesulfonate were used. This
thermoplastic resin composition for purging was used to conduct the
purging test (1). As a result, the required amount of the purging
thermoplastic resin composition was 0.6 kg and that of the polypropylene
as a succeeding resin for purging was 0.9 kg. The time period required was
18 minutes.
Example 11
A thermoplastic resin composition for purging (property: light yellow) was
obtained in the same manner as in Example 1, except that 4.65 kg (93.0 wt
%) of an ABS resin having a specific gravity of 1.03 and an MFR (2) of 0.4
g/10 min (PA-709, manufactured by Chimei Corporation), 0.10 kg (2.0 wt %)
of the MMSC, and 0.25 kg (5.0 wt %) of sodium dodecylbenzenesulfonate were
used. This thermoplastic resin composition for purging was used to conduct
the purging test (2). As a result, the required amount of the purging
thermoplastic resin composition was 0.5 kg and that of the ABS resin as a
succeeding resin for purging was 1.1 kg. The time period required was 20
minutes.
Example 12
A thermoplastic resin composition for purging (property: light yellow) was
obtained in the same manner as in Example 1, except that 3.9 kg (78.0 wt
%) of an ABS resin having a specific gravity of 1.03 and an MFR (2) of 0.4
g/10 min (PA-709, manufactured by Chimei Corporation), 0.6 kg (12.0 wt %)
of the MMSC, and 0.5 kg (10.0 wt %) of sodium dodecylbenzenesulfonate were
used. This thermoplastic resin composition for purging was used to conduct
the purging test (2). As a result, the required amount of the purging
thermoplastic resin composition was 1.2 kg and that of the ABS resin as a
succeeding resin for purging was 2.2 kg. The time period required was 41
minutes.
Example 13
A thermoplastic resin composition for purging (property: light yellow) was
obtained in the same manner as in Example 1, except that 2.75 kg (55.0 wt
%) of an ABS resin having a specific gravity of 1.03 and an MFR (2) of 0.4
g/10 min (PA-709, manufactured by Chimei Corporation), 0.60 kg (12.0 wt %)
of the MMSC, and 1.65 kg (33.0 wt %) of sodium dodecylbenzenesulfonate
were used. This thermoplastic resin composition for purging was used to
conduct the purging test (2). As a result, the required amount of the
purging thermoplastic resin composition was 1.7 kg and that of the ABS
resin as a succeeding resin for purging was 2.8 kg. The time period
required was 55 minutes.
Example 14
A thermoplastic resin composition for purging (property: milk-white) was
obtained in the same manner as in Example 1, except that 3.4 kg (68.0 wt
%) of polystyrene having a melt flow rate (JIS K7210: 200.degree. C.,
49.03 N load; hereinafter abbreviated as MFR (4)) of 0.5 g/10 min and a
density (specific gravity) of 1.05, 0.35 kg (7.0 wt %) of the MMSC, and
1.25 kg (25.0 wt %) of sodium dodecylbenzenesulfonate were used. This
thermoplastic resin composition for purging was used to conduct the
purging test (2). As a result, the required amount of the purging
thermoplastic resin composition was 0.8 kg and that of the ABS resin as a
succeeding resin for purging was 2.3 kg. The time period required was 38
minutes.
Example 15
A thermoplastic resin composition for purging (property: milk-white) was
obtained in the same manner as in Example 1, except that 4.2 kg (84.0 wt
%) of a powder obtained from colorless and transparent poly(ethylene
terephthalate) bottles used once for drinking water by washing the bottles
with water to remove foreign matters, pulverizing the washed bottles with
a pulverizer to an average particle diameter of from 0.2 mm to 1.0 mm, and
then vacuum-drying the particles at 80.degree. C. for 2 hours, 0.4 kg (8.0
wt %) of the MMSC, and 0.4 kg (8.0 wt %) of sodium
dodecylbenzenesulfonate. This thermoplastic resin composition for purging
was used to conduct the purging test (2). As a result, the required amount
of the purging thermoplastic resin composition was 0.6 kg and that of the
ABS resin as a succeeding resin for purging was 2.7 kg. The time period
required was 40 minutes.
Comparative Example 1
An ABS resin (property: light yellow) having a specific gravity of 1.05 and
an MFR (2) of 9 g/10 min (trade name, ABS 45; manufactured by Japan
Synthetic Rubber Co., Ltd.) was used as a thermoplastic resin composition
for purging to conduct the purging test (2). As a result, the total amount
of the ABS resin as a purging thermoplastic resin composition and the ABS
resin as a succeeding resin for purging was 8.0 kg and the time period was
98 minutes.
Comparative Example 2
A thermoplastic resin composition for purging (property: milk-white) was
obtained in the same manner as in Example 1, except that 4.6 kg (92.0 wt
%) of polypropylene having an MFR (1) of 9 g/10 min and a crystal melting
point of 165.degree. C., 0.3 kg (6.0 wt %) of sodium
dodecylbenzenesulfonate, and 0.1 kg (0.2 wt %) of polyethylene wax were
used. This thermoplastic resin composition for purging was used to conduct
the purging test (1). As a result, the required amount of the purging
thermoplastic resin composition was 3.5 kg and that of the polypropylene
as a succeeding resin for purging was 2.5 kg. The time period required was
74 minutes.
Comparative Example 3
A thermoplastic resin composition for purging (property: light yellow) was
obtained in the same manner as in Example 1, except that 4.3 kg (86.0 wt
%) of an ABS resin having a specific gravity of 1.03 and an MFR (2) of 0.4
g/10 min, 0.2 kg (4.0 wt %) of the calcium salt of a boric ester of
stearic acid monoglyceride, and 0.5 kg (10.0 wt %) of calcium carbonate
were used. This thermoplastic resin composition for purging was used to
conduct the purging test (2). As a result, the required amount of the
purging thermoplastic resin composition was 2.8 kg and that of the ABS
resin as a succeeding resin for purging was 2.2 kg. The time period
required was 61 minutes.
Comparative Example 4
A thermoplastic resin composition for purging (property: milk-white) was
obtained through mixing and melting in the same manner as in Example 1,
except that 3 kg (60 wt %) of a methyl methacrylate/styrene copolymer
having a melt flow rate (JIS K7210: 200.degree. C., 66.19 N load;
hereinafter abbreviated as MFR (5)) of 1.5 g/10 min, a density of 1.09,
and a number-average molecular weight of 250,000 (Estyrene MS-300,
manufactured by Nippon Steel Chemical Co., Ltd.) and 2 kg (40 wt %) of
sodium dodecylbenzenesulfonate were used. This thermoplastic resin
composition for purging was used to conduct the purging test (2). As a
result, the required amount of the purging thermoplastic resin composition
was 3.1 kg and that of the ABS resin as a succeeding resin for purging was
2.8 kg. The time period required was 72 minutes.
Example
1 2 3 4
5 6 7 8 9 10
Component Polypropylene (%) 96.0 99.5 -- -- -- --
80.0 99.3 91.8 --
proportion in High-density polyethylene (%) -- -- 89.0 -- -- --
-- -- -- 80.0
thermo- ABS resin (%) -- -- -- 81.0 67.0 --
-- -- -- --
plastic Polystyrene (%) -- -- -- -- -- 73.0 --
-- -- --
resin Methyl methacrylate/styrene copolymer (%) 4.0 0.5 11.0
19.0 33.0 27.0 10.0 0.2 0.2 5.0
composition Sodium dodecylbenzenesulfonate (%) -- -- -- -- -- -- 10.0
0.5 8.0 15.0
for purging Polyethylene wax (%) -- -- -- -- -- -- -- --
-- --
(Note 1) -- -- -- -- -- -- -- --
-- --
Calcium carbonate (%) -- -- -- -- -- -- -- --
-- --
Purging test Use amount of the thermoplastic resin 1.1 2.3 0.6 0.6
1.6 0.7 1.0 2.4 1.7 0.6
composition for purging (kg)
Use amount of polypropylene or ABS resin (kg) 1.3 1 .7 0.9
1.5 2.3 1.9 1.4 1.3 1.5 0.9
Purging period (min) 29 49 18 26
47 32 29 45 39 18
(Note 1) Calcium salt of boric ester of stearic acid monoglyceride (%)
Example
Comparative Example
11 12 13 14
15 1 2 3 4
Component Polypropylene (%) -- -- -- -- -- -- 92.0
-- --
proportion in High-density polyethylene (%) -- -- -- -- -- -- -- --
--
thermo- ABS resin (%) 93.0 78.0 55.0 --
-- 100 -- 86.0 --
plastic Polystyrene (%) -- -- 68.0 -- -- -- --
-- --
resin Methyl methacrylate/styrene copolymer (%) 2.0 12.0 12.0
7.0 8.0 -- -- -- 60.0
composition Sodium dodecylbenzenesulfonate (%) 5.0 10.0 33.0 25.0
8.0 -- 6.0 -- 40.0
for purging Polyethylene wax (%) -- -- -- -- -- -- 2.0
-- --
(Note 1) -- -- -- -- -- -- -- 4.0
--
Calcium carbonate (%) -- -- -- -- -- -- -- 10.0
--
Reclaimed poly(ethylene terephthalate) (%) -- -- -- -- 84.0
-- -- -- --
Purging test Use amount of the thermoplastic resin 0.5 1.2 1.7 0.8
0.6 -- 3.5 2.8 3.1
composition for purging (kg)
Use amount of polypropylene or ABS resin (kg) 1.1 2.2 2.8
2.3 2.7 8.0 2.5 2.2 2.8
Purging period (min) 20 41 55 38
40 98 74 61 72
(Note 1) Calcium salt of boric ester of stearic acid monoglyceride (%)
POSSIBILITY OF INDUSTRIAL APPLICATION
The thermoplastic resin compositions for purging according to the present
invention each is a purging thermoplastic resin composition having an
exceedingly high cleaning ability when used for the purging of an
injection-molding machine or extruder in which a resin used for injection
molding or extrusion molding is tenaciously adherent to the inside of the
apparatus due to pyrolysis to make it difficult to clean the apparatus.
The thermoplastic resin compositions for purging according to the present
invention, even when used in a small amount, are far more effective than
conventional purging thermoplastic resin compositions in reducing the use
amount of a succeeding resin for purging. The compositions of the present
invention are also effective in reducing the purging period.
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